1. Field of the Invention
This invention relates to a foamable sodium percarbonate bleaching agent having an excellent solution velocity and which foams vigorously when added to water.
2. Description of the Prior Art
There are known both oxygen-type bleaching agents and chlorine-type bleaching agents. In Japan, chlorine-type bleaching agents having an excellent bleaching effect at a low temperature have been in general use. Although the chlorine-type bleaching agents are effective on cellulosic fibers, they have a disadvantage in that they cannot be used for some synthetic fibers because they cause yellow stain damage of synthetic fibers. Another disadvantage of the chlorine-type bleaching agents is that they decolorize dyed clothing made from synthetic fibers.
On the other hand, the oxygen-type bleaching agents have advantages in that they can be used for treating most synthetic fibers in addition to cellulosic fibers, and they can be used safely for dyed clothing, because their bleaching actions are mild.
However, the oxygen-type bleaching agents, a typical example of which is sodium percarbonate, have only a poor solution velocity at low temperatures and therefore a sufficient bleaching power cannot be obtained. Further, because of their poor solution velocity, the remaining undissolved particles of the bleaching agents stick to the fibers and cause partial, excessive bleaching zones, whereby the fibers are damaged and partially decolorized. Accordingly, oxygen-type bleaching agents have been not used in Japan in situations wherein clothes washing is generally effected at a low temperature of about 20.degree.C, although they are effective if they are used for washing at a high temperature of above 60.degree.C. In view of these circumstances, improvements in the solution velocity of oxygen-type bleaching agents has been desired.